This application relates to a cooling hole array for use adjacent a leading edge of an airfoil.
Gas turbine engines are known and, typically, include a fan delivering air into a compressor where it is compressed. The compressed air is delivered into a combustion section where it is mixed with fuel and ignited. Products of this combustion pass downstream over turbine rotors driving them to rotate.
The turbine section typically includes rotating blades and static vanes, all of which include airfoils. The airfoils are exposed to very hot temperatures and, thus, internal cooling passages are provided within the airfoils.
Airfoils extend from a leading edge to a trailing edge and have a suction and pressure side. Cooling has typically been provided adjacent the leading edge with so-called “showerhead” hole shapes. A showerhead shape has a longer dimension and a shorter dimension and the longer dimension is typically aligned with a radial direction along the airfoil.
More recently, so-called “high lift” aerodynamic airfoils have been developed. A high lift airfoil maximizes the ability of the turbine to capture energy from the working fluid, thereby reducing the need for increasing the flow of working fluid through the turbine and increasing turbine performance.
The use of showerhead cooling holes at the leading edge of high lift airfoils requires some unique characteristics at least partially because the cooling holes have typically been provided at a mechanical leading edge, whereas the actual aerodynamics in a high lift airfoil result in a distinct location of airflow split extending onto the pressure side of the airfoil and, in particular, at radially inner locations.